Clamping device



Aug, 6, 19400 c, H K EJ Er AL 2.210587 CLAMPING DEVICE Filed 001:. 7, 1939 F76 7 INVENTORv (War/6; H K/em Zeroy H. gar/w oman..*.;--

UNITED ST ES PATENT OFFICE 7 cmtmmo novice Charles R. Klein and Leroy H. Burns, Cleveland,

Ohio, asslinors to The National Telephone Supply Company Application October '1, 1939, Serial No. 298,511 14 Claims. (01. 16-108) Our invention relates to clamps and more parc s g the c es w c a e held y t e 'ticularly clamps for clamping armor rods about elelnpelectric conductors. 1 A further object of our invention is to reduce An object of our, invention is-t provide a stress concentrations in the O clamp and to clamp for armor rods which can be easily placed thereby prevent the crushing of a cable inside 5 ,around the armor rods and forced into engagethe pment therewith. Other objects and a fuller understanding of Another object of our invention is to provide our invention may be had by referring to the an armor rod elam whi h a b readily and following description and claims, taken in consafely attached to electric conductors suspended J c h e ac pfl g drawing, in 10 above the ground. I which: e

Another obj t. of ou i ntio i t provide Figure 1 is a side view of our invention showa C clamp with a side opening which permits the ing a plurality of armor rods fastened around a clamp to be slipped over the armor rods or wires conductor b e y m s of o psfrom the side thereby enabling the clamps to Figure 2 s a s e V w Of 1' mp in its pe 15 be used when each end of the armor rods 'or Condition. 1

wires is obstructed by a large twisting wrench. F e 3 s a fragmentary side View Of a Clamp- Another object of our invention is the proing tool and a c amp afte e clamping tool has vision of a clamp which will retain itself into a been operated to close the clamp.

clamping tool as the linesman operates the tool gu e 4 s an e a d t sve se V ew of the 2 to depress the clamp about the armor rods or outline of the clamp prior to being closed about wires. 1 the armor-rods and showing a part of the law A further object of our invention is to furnish of a elampins o i he re nin roove bu an armor rod attaching clamp for use with a, before it has come in contact with the clamp.

bending tool and to provide for inserting the Fi ure 5 is an enlarged transverse view of the 25 clamp into the tool in'such a manner that the outline of the clamp after being closed about the clamp will' stay in the tool while it is being armor d extended far out from the pole on which the igu e 6 s a fro t eleva ion o a twisti linesman is situated. wrench which is used to wind the armor rods Another object of our invention is to provide 1 about the conductor cable, and 30 for easily. disengaging the tool from the clamp Figure '7 is a View of one of the twisting after the clamp has been clamped onto the wrenches in place on the armored electric conarmor rods. ductor cable and also showing one 01' our clamps Still another object of our invention is to -furin p ce 5 nish a method for attaching armor/rods to an Fi ure 8 is a View s l r to Figure 4 w g electric conductor. another embodiment of our invention without Another object of our inventionis to provide h wing h cl mpin ol; n a c clamp having a groove into which the bend- Figure 9 s a v w similar to Figure 8 sh win me tool fits and to provide a raised portion in I still another embodiment of1 our invention. 40 the groove which insures that the bending tool with reference to Figure of the g, we 40 contacts theycenter f the clamp have shown an electric conductor or cable 9 I A Iurther object of our invention is to provide pp reinforced with plurality of armor a raised portion in the retaining groove which was or wnjes n having ends held in the t twisted position by means of our improved clamp assures hat the Contact between tool Jaw Ill' The entire assembly may be suitably fasw and the clamp is Small in F tenedto an insulator l5 by tie wire means I 6 in Sim 9 M Our Invention is to accordance with the usual practice. The armor vide a camp orauminum armor rods which n r ab] a1 1 m m is applied by the action of a toggle tool andto rods e p er y um nu a d ay vary 7 v in length from approximately 3, to 5 feet and guard'agalnst crushing of the aluminum armor are designed to prevent abrasion of the conrods by Providing g h o in the clamp- Yductor 9 from the tie wires and insulators, as Ano her obtleet f our invention s to P i well as reduce the fatigue from vibration. A1-

a c clamp which distributes the o eeo a to g e though primarily a reinforcement, the armor tool substan ally evenly along the inside sur-, rods II have a dampening eiiect which reduces face of the c amp thereby reducing the danger the amplitude of vibration of the conductor or cable 9 as much as 10 to 20 per cent. An addi-' tional advantage of considerable value is the protection of the cable 9 from flashover burns. The

lay or twist of the armor rods l1 are in the same direction as the lay or twist of the strands of the cable 9.

The clamps iii are open forming a c construction and are placed around each end of the armor rods H to snugly hold the armor rods in place. As these conductors 9 are usually upon a high pole and mounted at the ends of long cross arms it is not easy for a'linesman to reach several feet out along the line to attach a clamp;

To facilitate the fastening of the clamp to the armor rods or wires, we have devised the clamp ||l which can be inserted into the jaws |9 of a tool 29 and extended out to the point where the clamp is to be attached. There the tool 20 is operated and the clamp is securely fastened.

Our clamp Ill comprises an open ring or C clamp having an' internal surface II which is adapted to grip the armor rods or wires 11. Our. clamp .Ill also has an external surface |2 with a groove l3 therein. adapted to receive the jaws l9 of the tool 20. An opening I! is provided to enable the clamp ill to slip over the' armor rods or wires H. The clamp I0 is preferably made of the same kind of metal as the armor rods or wires which it engages to prevent electrolytic corrosion.

For twisting the armor rods |1 about the electric conductor 9, we utilize a pair of twisting wrenches 2| each having a set of split dies 23 to receive the ends of the armor rods l1.

Each pair of split dies 23 are placed around the electric conductor wire 9 and then the twisting wrench .2| is fastened around the dies 23 by means of the wing nut 22. A plurality of armor rods H are then laid parallel to the electric conductor wire 9 with their ends through the holes 24 in the split dies. wrenches are-then moved inwardly and spaced apart equal to approximately one-third the length ofthe armor rods. The central one-third length of the armor rods I1 is then twisted until the armor-rods |1 snugly engage the electric conductor wire 9. The wrenches are then moved to the end positions and the remainder of the length of the armor rods I1 is twisted snugly about the electric conductor wire 9. The lay or twist of the armor rods l1 should be in the same direction as the lay or twist of the cable strands of the electric conductor wire or cable 9. The twisting wrenches 2| are then held in place in any convenient manner such as attaching a weight to one end of the handle to hold the armor rods or wires IT in their. twisted condition, thereby freeing both of the linesmans hands to attach the clamps Ill.

The open 0 clamp I0 is then placed in the jaws of the clamping tool 20 where the groove |3 engages the sides of the jawsv l9 to retain the 0 clamp therein. The clamp I9 isthen placed over the twisted armor rods |1 just inside one of the twisting wrenches 2| and the handles 25, of the clamping tool are pressed to forcibly close the 6 clamp on the armor rods l1. Upon relieving the pressure on the handles 25 the jaws l9 of the tool will disengage from the closed c clamp and permit the easy removal therefrom. A second C clamp is then pressed into place at the other end of the armor rods l1 after which the twisting wrenches 2| may be removed. The clamping tool 29 which is used to close the clamp I0 is a constant movement tool; that Both of the twistin is to say, the moving jaws of the tool close to a constant position. For this reason slight variations in the size of the armor wires l1 and the clamp 19 may cause excessive pressures on the aluminum armor rods and the electric conductor cable 9 when the clamp is closed to the limit of the tool movement. Crushing of the aluminuin armor rods and the electric conductor cable 9 may also occur if the tool-20 is adjusted too tight. The crushing of the aluminum rods l1 and of the electric conductor cable 9 is undesirable due to the possibility of vibration'fatigue failure at the crushed points. The clamp l9 has been designed to obviate this possibility.

One safety feature of our clamp ID is the raised W central portion 21 of groove I3 which centers the pressure from the jaw |9 of the tool 20 and provides a limited area of contact between the tool 20 and the'clamp. The limited area of contact establishes a crushing zone about the raised central portion 21. The crushing zone 21 reduces the danger of crushing the aluminum armor wires l1 when the clamp is closed about the rods because if any crushing takes place, it will occur in the crushing-zone 21 and relieve the pressure on the armor rods |1.

Another feature of our clamp nally arcuate' internal surface 28 which'is divided into a left end engaging zone 39, a. right end engaging zone 3| and a central engaging zone 29; see Figure 4 where the surface of the armor is the longitudi- I rods or wires is indicated by the dash-dot line 7 i8. As the clamp III is closed about the armor rods or wires l1 by the action of the clamping tool 2|] the end engaging zones 30 and 3| engage the armor rods |1 first to create what might be called a "two zone engagement."

engaging zones are in firm contact with the armor rods |1, pressure from the clamping tool 20 causes the clamp III to depress radially until the central engaging zone 29 firmly engages the armor rods l1, (see Figure 5) to create what might be called a three zone engagement. At this point the clamping tool 20 should have reached the closed end of its constant movement.

After the end If, however, the tool 20 has not reached the end of its compressive movement, the crushing zone around the central point 21 will crush instead of the internal surface damaging the aluminum armor rods l1 and the electric conductor cable 9 as the tool 29 is closed to its limit. 0n the other hand, should slight variations in the clamping tool 20, the clamp ID, the armor rods l1 and the electric conductor cable 9 combine to prevent the tool from firmly clamping the central engaging zone 29 against the armor rods I1, then in this case the clamp In still firmly engages the armor rods as both of the end engaging zones 39 and 3| are depressed tight against the armor rods |1 establishing "two zone engagement.

It is to be seen, therefore, that our clamp l0 provides safety features to insure a good clamping action regardless of slight variations inthe clamp, the armor rods and the electric conductor cable 9. Should the variations result in the constant movement clamping tool 20 depressing the clamp too hard over and above that required to make a firm three zone engagement, then the crushing zone 21 functions to relieve the armor rods and the electric conductor cable 9 from being damaged. Should the variations manifest themselves in the reverse manner, the clamp I. still makes a good firm engagement because a positive two' zone engagemen is effected even 2,210,587 may not g a tablish a crushing'zone, said clamp having a longitudinally arcuate internal surface creating end engaging zones and a central engaging zone, said clamp being arranged to close radially upon pressure from said clamping tool and force said end enga in rang-said qantralsu zone *iritdengagenientwith said" though the constant movement" clamp depress the central engaging zone 29 against the armor rods.

oi'ighout said ofcontact 'be- Q lam'ping'; tool to' es- .thetclampin tool jaws I9 The walls 3 r t e t d n od Li E y f i S ot-av a sg'it z gm; L Q" in the details of cons ruc ion may b'resorted to withg u t depart i ng frgm the spirit and the scope oftl 'eht ofi-fi asfghgreinafter claimed.

We claim as our ifivntion: Y 1. A clamp arranged for use with a clamping tool and adapted for fastening armor wire around a conductor comprising, an open and expanded metallic C clamp having an external surface with a groove therein for receiving said clamping tool, said groove having a curved bottom extending outwardly toward the said external surface and converging side walls extending from the external surface to the curved bottom, the juncture between the side walls and the curved bottom being arcuate-to strengthen the said juncture, said side walls retainingsaid clamp inengagement with said clamping tool and said curved bottom centering the pressure from said clamping tool and providing a limited area of contact between said clamp and said clamping tool to es- D 6. A clamp arranged for use with a clamping tool and adapted for encircling wire comprising,

with a groove therein for receiving said clamping tool, said groove having a bottom with an arcuate raised portion adapted to receive pressure from said clamping tool and distribute it through the said clamp for compressing same about the wire.

'7. A clamp arranged for use with a clamping tool and adapted for encircling wire comprising, an open 0 clamp having an external surface with a groove therein for receiving said clamping tool, said groove having a bottom with a substantially triangular raised portion adapted to receive pressure from said clamping tool and disan open 0 clamp having an external surface tribute it through the said clamp for compressing same about the wire.

8. A clamp arranged for use with a clamping tool and adapted for encircling wire comprising, an open 0 clamp having an external surface with a groove therein for receiving said clamp:- ing tool, said groove having a bottom with a substantially rectangular raised portion adapted to receive pressure from said clamping tool and distribute it through the said clamp for compress-' ing same about the wire.

9. A clamp arranged for use with a clamping tool and adapted for fastening wires together comprising, a clamp having an internal surface adapted to engage said wires and an external surface with a groove therein for receiving said clamping tool, said groove having bottom means and side wall means, said bottom means comprising portions relatively nearsaid internal surface and portions relatively farther away from said internal surface, said side wall means extending from the said external surface to the porface adapted to engage the material to be clamped and an external surface adapted to be engaged by said clamping tool, said internal surface being arcuate to create end engaging zones and a central engaging zone, the end engaging zones being adapted to engage the material to be clamped before the central engaging zone, said external surface having a groove therein adapted to receive said clamping tool, said groove comprising side wall means converging toward the said internal surface and bottom means, said bottom means comprising portions joining said side wall means and a raised portion to establish a limited area adapted to engage the said clamping tool.

11. A clamp arranged'for use with a clamping tool comprising, a body having an internal surface and an external surface, said internal surface being adapted to engage a material to be clamped and said external surface having a 4 groove therein adapted to receive said clamping tool and means in said groove adapted tocenter pressure from said clamping tool and transmit it throughout the width of the internal surface of the said clamp.

12. A clamp arranged for use with a clamping tool comprising a body having an internal surface adapted to engage a material to be clamped, said internal surface being longitudinally arcuate to 'create end engaging zones and 'a central engaging zone, and an external surface having a groove therein substantially radially outwardly from said central engaging zone, said groove having a bottom. with a portixn'thereof raised to establish a limited area for contacting said clamping tool and for centering the pressure from the said tool, said groove alsohaving side walls adapted to retain said clamp in engagement with said clamping tool, said side walls converging toward said internal surface to prevent the clamp from binding the tool as pressure from said tool bends said clamp to cause the said central engaging zone to engage the material to be clamped.

13. A clamp arrangedfor use with a clamping tool and adapted for encircling wire comprising, an open 6 clamp having an external surface with a groove therein for receiving said clamping tool and an internal surface adapted to engage said wire to be clamped, said groove comprising side wall means and bottom means adapted to cooperatively retain said 6. clamp in said clamping tool while said 0 clamp is being closed about said wire and said bottom means transmitting. the pressure exerted by said clamping tool to said internal surfacefor compressing same about'the wire.

14. A-clamp arranged for use with a clamping tool and adapted for encircling wire comprising, an open 6 clamp having an external surface with a groove therein for receiving said clamping tool and an internal surface adapted to engage said wire to be clamped, said groove comprising side wall means and bottom means adapted to cooperatively retain said O clamp in said clamping tool while said 6 clamp is being closed about said wire and said bottom means transmitting the pressure exerted by said clamping tool to said internal surface for compressing same about the wire, the juncture between the side wall means and the bottom means being arcuate.

CHARLES H. LEROY n. norms. 

